The external ear, also known as the auricle, is an important bilateral organ that allows convergence of sound waves to the middle and inner ear, allowing for the detection of sounds by the brain. Furthermore, auricles provide an important function in supporting glasses in patients who require vision correction. Additionally, auricles represent important aesthetic subunits of the human face due to their central position and clear visibility. Any alteration of its shape either from birth or acquired (after a trauma) represents a significant psychological burden for patients worldwide.
Microtia is a common malformation that presents with an abnormally shaped absent ear at birth. It has been calculated that microtia occurs at a rate of 0.83 to 17.4 per 10,000 live births in the general population. This range varies among regions, and is higher in Hispanics, Asians, Native Americans, and Andeans. Although this number may seem small, the number of cases present in the general population at any time is high and correction of ear deformity is in demand in these young patients.
Currently, the so-called Nagata technique represents the gold standard for surgical treatment of such deformities. In this long and technically challenging surgical technique, a large fraction of rib cartilage from the patient is harvested, and the surgeon, typically a plastic and reconstructive surgeon, carefully carves the rib cartilage to create several pieces that combined in a complex construct create a mold of the ear similar to that of the normal ear. This cartilage is then implanted under the skin where the ear is missing. Alternatively, a cadaver donor is used and the rib cartilage is available for immediate molding by the surgeon. Either way, this technique helps to restore ear form and function. The presence of a plastic surgeon who has obtained specific and additional training to perform such procedures is mandatory for a successful ear reconstruction with this technique. Surgeon-to-surgeon variability in skill sets in cartilage carving techniques render results suboptimal in some cases.
In addition to malformations like microtia, which are present since birth, acquired ear deformities are extremely common, accounting for a high percentage of all facial plastic surgery consults requested by Emergency Departments worldwide. These include trauma, such as dog bites or combat wounds, or resection to eradicate cancers, such as melanoma and non-melanoma skin cancers. Despite the finest reconstructive efforts, replantation of these ears are often not successful, leaving the patient malformed and without an auricle. These deformities, either congenital (from birth) or acquired (for trauma) can involve other cartilages in the body, including the nose cartilage. The nose is made of several pieces of cartilage that combined together create the septum, the lateral walls and the tip. For this reason, rhinoplasty, either for reconstructive purposes after trauma or for cosmetic purposes is one of the most complex and sought after procedures in Plastic Surgery. Eyelid (tarsus) reconstruction is another common reconstructive procedure for cosmetic and medical purposes, requiring a thin disc of cartilage to provide the framework for the final structure.
Existing patents do not appear to describe a process of developing a model of the human ear, nose, or eyelid cartilage from existing body tissues using a mechanical device. No patents exist that describe the development of implantable models of human ear, nose, or eyelid cartilage from either autologous cartilage or synthetic materials.
Patents related to the background of the invention include U.S. Pat. Nos. 6,491,511B1, 5,571,174A, 5,662,705A, and 5,326,371A, which detail the development of heart valves from pericardial tissue using shape specific dies. However, the quality of tissue is vastly different from the dense material required for cartilaginous structures. Additionally, they describe no overall processing of individual components into more complex structures, which is a notable feature according to the present invention, allowing for intricate 3-dimensional shapes to be generated from the original substrate. Other patent publications, such as US20140228953A1, US20110264236A1, and US20090018465A1 describe a preformed and implantable model of the ear. Aesthetic success of such implants can be limited, as the body's immune system typically reacts against foreign materials. As a result, the best results will be achieved by reshaping tissue generated from the patient's own cartilage, a process not addressed by existing patents.
In addition, U.S. Pat. No. 9,149,295 describes a system that harvests cartilage, trims and cuts it using a punch system, with a variety of cutters, to create precise configurations for tympanoplasty reconstructions. The present invention, however, has cutters shaped for ears, noses, and eyelids (not tympanic membrane), and the present invention mechanisms of action are larger presses, which the '295 patent system does not utilize. U.S. Pat. No. 8,535,315 describes a guillotine-like device to cut thin slices of costal cartilage of user-defined thickness. Vertical cutting of the cartilage is less advantageous and less accurate than the horizontally oriented blade according to the present invention. The thickness in the '315 patent is determined by blade separation, versus the present invention, which uses a vertically adjustable platform to position the cartilage at a specific height for precise cutting. U.S. Pat. No. 8,562,614 describes a disposable cartilage cutter featuring two plates with recesses that allow cartilage to form discs as a blade cuts the cartilage between the plates, leaving behind discs of cartilage that were located in the recess. This is a form of a thickness cutter, but the present invention uses a longitudinal blade on a vertically adjustable platform, and is adaptable to any shape and range of thickness (not just preformed discs). U.S. Pat. No. 6,491,511 describes molds for cutting of flat membranous tissue into specific a configuration that results in formation of heart valves to be used in cardiac surgery. Instead, the present invention focuses on ear/nose/eyelid, not heart valve shapes and configurations.
Other generally-related art include the following US patent documents:
U.S. Pat. No. 8,568,480—Joint arthroplasty devices and surgical tools.
U.S. Pat. No. 7,618,653—Biological artificial nerve guide and method of marking.
U.S. Pat. No. 7,156,814—Apparatus and method for harvesting and handling tissue samples for biopsy analysis.
U.S. Pat. No. 8,028,837—Break-open package with shaped die cut for storing and dispensing substrates.
U.S. Pat. No. 7,229,820—Apparatus and method for culturing and preserving tissue constructs.
U.S. Pat. No. 6,027,773—Specialty die cut confetti and method of manufacture.
U.S. Pat. No. 5,788,625—Method of making reconstructive SIS structure for cartilaginous elements in situ.
U.S. Pat. No. 5,653,749—Prefabricated, sterile, disposable kits for rapid assembly of a tissue heart valve.
U.S. Pat. No. 5,609,600—Tissue cutting die.
U.S. Pat. No. 5,425,741—Tissue cutting die.
U.S. Pat. No. 5,326,370—Prefabricated sterile and disposable kits for the rapid assembly of a tissue heart valve.
20120189669—Solid forms for tissue repair.
20100075896—Repair of larynx, trachea, and other fibrocartilaginous tissues.
20080039954—Expandable cartilage implant.
20070270948—Methods and composition for soft tissue feature reconstruction.